X-Git-Url: https://git.netwichtig.de/gitweb/?a=blobdiff_plain;f=src%2Fsrc%2Ftls.c;h=d47156cdc5ea555778ce3a5e4ea15378a775aa57;hb=30398c0651d976f7ca2713ba9441c117eb37ed1e;hp=1fd10d52b374000a425166f90804a88482076aea;hpb=01603eec64d42431f182b33008206facfc7f800e;p=user%2Fhenk%2Fcode%2Fexim.git

diff --git a/src/src/tls.c b/src/src/tls.c
index 1fd10d52b..d47156cdc 100644
--- a/src/src/tls.c
+++ b/src/src/tls.c
@@ -19,6 +19,11 @@ functions from the OpenSSL or GNU TLS libraries. */
 #include "exim.h"
 #include "transports/smtp.h"
 
+#if !defined(DISABLE_TLS) && !defined(USE_OPENSSL) && !defined(USE_GNUTLS)
+# error One of USE_OPENSSL or USE_GNUTLS must be defined for a TLS build
+#endif
+
+
 #if defined(MACRO_PREDEF) && !defined(DISABLE_TLS)
 # include "macro_predef.h"
 # ifdef USE_GNUTLS
@@ -48,7 +53,7 @@ We're moving away from this; GnuTLS is already using a state, which
 can switch, so we can do TLS callouts during ACLs. */
 
 static const int ssl_xfer_buffer_size = 4096;
-#ifndef USE_GNUTLS
+#ifdef USE_OPENSSL
 static uschar *ssl_xfer_buffer = NULL;
 static int ssl_xfer_buffer_lwm = 0;
 static int ssl_xfer_buffer_hwm = 0;
@@ -56,8 +61,6 @@ static int ssl_xfer_eof = FALSE;
 static BOOL ssl_xfer_error = FALSE;
 #endif
 
-uschar *tls_channelbinding_b64 = NULL;
-
 
 /*************************************************
 *       Expand string; give error on failure     *
@@ -122,14 +125,14 @@ tzset();
 #ifdef USE_GNUTLS
 # include "tls-gnu.c"
 # include "tlscert-gnu.c"
-
 # define ssl_xfer_buffer (state_server.xfer_buffer)
 # define ssl_xfer_buffer_lwm (state_server.xfer_buffer_lwm)
 # define ssl_xfer_buffer_hwm (state_server.xfer_buffer_hwm)
 # define ssl_xfer_eof (state_server.xfer_eof)
 # define ssl_xfer_error (state_server.xfer_error)
+#endif
 
-#else
+#ifdef USE_OPENSSL
 # include "tls-openssl.c"
 # include "tlscert-openssl.c"
 #endif
@@ -226,7 +229,7 @@ modify_variable(US"tls_bits",                 &dest_tsp->bits);
 modify_variable(US"tls_certificate_verified", &dest_tsp->certificate_verified);
 modify_variable(US"tls_cipher",               &dest_tsp->cipher);
 modify_variable(US"tls_peerdn",               &dest_tsp->peerdn);
-#if !defined(DISABLE_TLS) && !defined(USE_GNUTLS)
+#ifdef USE_OPENSSL
 modify_variable(US"tls_sni",                  &dest_tsp->sni);
 #endif
 }
@@ -364,6 +367,81 @@ else if ((subjdn = tls_cert_subject(cert, NULL)))
   }
 return FALSE;
 }
+
+
+
+/*************************************************
+*       Drop privs for checking TLS config      *
+*************************************************/
+
+/* We want to validate TLS options during readconf, but do not want to be
+root when we call into the TLS library, in case of library linkage errors
+which cause segfaults; before this check, those were always done as the Exim
+runtime user and it makes sense to continue with that.
+
+Assumes:  tls_require_ciphers has been set, if it will be
+          exim_user has been set, if it will be
+          exim_group has been set, if it will be
+
+Returns:  bool for "okay"; false will cause caller to immediately exit.
+*/
+
+BOOL
+tls_dropprivs_validate_require_cipher(BOOL nowarn)
+{
+const uschar *errmsg;
+pid_t pid;
+int rc, status;
+void (*oldsignal)(int);
+
+/* If TLS will never be used, no point checking ciphers */
+
+if (  !tls_advertise_hosts
+   || !*tls_advertise_hosts
+   || Ustrcmp(tls_advertise_hosts, ":") == 0
+   )
+  return TRUE;
+else if (!nowarn && !tls_certificate)
+  log_write(0, LOG_MAIN,
+    "Warning: No server certificate defined; will use a selfsigned one.\n"
+    " Suggested action: either install a certificate or change tls_advertise_hosts option");
+
+oldsignal = signal(SIGCHLD, SIG_DFL);
+
+fflush(NULL);
+if ((pid = fork()) < 0)
+  log_write(0, LOG_MAIN|LOG_PANIC_DIE, "fork failed for TLS check");
+
+if (pid == 0)
+  {
+  /* in some modes, will have dropped privilege already */
+  if (!geteuid())
+    exim_setugid(exim_uid, exim_gid, FALSE,
+        US"calling tls_validate_require_cipher");
+
+  if ((errmsg = tls_validate_require_cipher()))
+    log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+        "tls_require_ciphers invalid: %s", errmsg);
+  fflush(NULL);
+  exim_underbar_exit(0);
+  }
+
+do {
+  rc = waitpid(pid, &status, 0);
+} while (rc < 0 && errno == EINTR);
+
+DEBUG(D_tls)
+  debug_printf("tls_validate_require_cipher child %d ended: status=0x%x\n",
+      (int)pid, status);
+
+signal(SIGCHLD, oldsignal);
+
+return status == 0;
+}
+
+
+
+
 #endif	/*!DISABLE_TLS*/
 #endif	/*!MACRO_PREDEF*/